1. Field of the Invention
The present invention relates to an ink supply device and its drive system used in an ink jet printer.
2. Description of the Related Art
An ink jet printer includes a recording head portion for ejecting liquid ink, a carriage mounted with the recording head portion, a mechanism for transporting the carriage in a main scanning direction, and another mechanism for transporting a recording sheet, such as a sheet of paper, in an auxiliary scanning direction, which is perpendicular to the main scanning direction.
Conventional hot melt ink jet printers use hot melt ink that is solid at room temperature and liquid when melted. The hot melt ink can be provided in pellet form. The recording head portion of hot melt ink jet printers includes: a nozzle head formed with a plurality of nozzles, a hopper portion for receiving and melting the ink pellets, and a heater for maintaining the melted condition of the hot melt ink. During printing, the carriage is transported in the main scanning direction while the recording head portion is driven to eject hot melt ink droplets from the nozzles of the nozzle head so that desired characters and/or images can be printed on the surface of the recording sheet.
When the recording head portion runs out of ink, the user has to drop some ink pellets into the hopper portion. The ink pellets are melted by the heater so the ink can be ejected from the nozzle head. When replenishing the ink pellets, the operator therefore has to pick up the ink pellets by hand. Accordingly, grime and oil from the operator's fingers can cling to the ink pellets and degrade the quality of the hot melt ink.
U.S. Pat. No. 4,823,146 has proposed a method for enabling replenishment of the ink pellets without requiring the user to directly touch the ink pellets.
According to this method, a flexible ink holder is provided to house an ink pellet therein. The flexible ink holder is formed from a flexible material. One end of the ink holder is open, and covered with a material, such as aluminum foil, that tears when applied with pressure. A plurality of different types of ink holders are provided, each housing a different colored ink pellet.
To supply an ink pellet, the user selects an ink holder containing a desired color of ink pellet. Then, the user places the ink holder against the opening of the hopper for the corresponding color so that the aluminum foil cover presses against the hopper opening. The user then fixes the ink holder in place in this posture. Then, the user presses against the rear side of the ink holder and presses toward the sealed portion. As a result, the rear side of the ink holder presses against the ink pellet, which in turn presses against and tears the aluminum foil cover. This configuration enables the user to replenish ink pellets without directly touching them.